Sugar Crystallization in Refinery HELP!?

Question

Can someone explain about what crystallization really like?? I know about all the super-saturation, but hey, please please tell me more about the mechanism, and the machine for the crystallization!

I need a good, clear, and in detail data!

Thank you very much! :)

Answer 1

The resulting clear juice is then evaporated in a partial vacuum and heated until it forms a thick syrup containing many crystals of sugar. The dense mass of crystals and syrup is known as massecuite. The massecuite is placed in a centrifuge turning at a rate of 1000 to 1500 rpm; the centrifuge walls are pierced by small holes through which the syrup, called molasses, is forced out during centrifuging. The yellowish or brown sugar removed during the centrifuging process is called first sugar, or raw sugar. The first sugar is sprayed with water to remove any molasses that may have clung to the crystals, and is then moved to the refinery. The molasses may be boiled again and reevaporated in an attempt to crystallize out some of the rich sucrose content of this liquid; in modern cane-sugar manufacture, the syrup is usually crystallized only once.

http://encarta.msn.com/encyclopedia_7615...

In such refineries, raw sugar is further purified. It is first mixed with heavy syrup and centrifuged to wash away the outer coating of the raw sugar crystals, which is less pure than the crystal interior. The remaining sugar is then dissolved to make a syrup (about 70 percent by weight solids) which is clarified by the addition of phosphoric acid and calcium hydroxide that combine to precipitate calcium phosphate. The calcium phosphate particles entrap some impurities and absorb others, and then float to the top of the tank, where they are skimmed off.

After any remaining solids are filtered out, the clarified syrup is decolorized by filtration through a bed of activated carbon. The purified syrup is then concentrated to supersaturation and repeatedly crystallized under vacuum to produce white refined sugar. As in a sugar mill, the sugar crystals are separated from the molasses by centrifuging. To produce granulated sugar, in which the individual sugar grains do not clump together, sugar must be dried. Drying is accomplished first by drying the sugar in a hot rotary dryer, and then by blowing cool air through it for several days.

http://en.wikipedia.org/wiki/Refinery